amp spike on carrier 5 ton heat pump

[bzzline]

One of the first jobs I did on a install with Carrier contractor was a tripping cb in heat mode turned out to be a fan relay wired wrong from the factory

[HVAC-Eng]

Usually motors draw more current upon start up. The induced emf (Electro Magnetic Field) in the motor's shaft depends on the rotation speed of the motor (at startup roter is at rest) so therefore the starting current (called inrush current) will be up to 10 times higher than the motor's rated current.

I suggest turning the units on one at a time.

[hvacmike85]

Actually had an electrician (experienced with own biz) tell me there was no such thing as a weak breaker!

anything is possible

[AddMore22]

Dumb idea .... But check lug connection on all electrical fittings going to main ...

[AddMore22]

Ps..
Did it trip when you tested it? What was volts?

[Tech it out]

anything is possible

Ive changed many over the years that had no where near the rated amps. Maybe we should start calling it "strength challenged" instead of weak!

[71CHOPS]

yeah, what's the LRA ratings on those units?? if they both started at the same time....or if the building amp draw was already high, and one kicked on,that might do it.

just looked at a 3ton residential rheem yesterday, it's comp. LRA was 112a.